1. Field of the Invention
The present invention relates to a cleansing/scraping technique for cleansing surfaces of a desired body, for example, from a large one such as a car, a railway vehicle, an aircraft, a building wall, or the like, to a relatively small one such as tableware, or the like, of stains adhering thereto, or for scraping adhesive matters such as a label, a coating, etc. adhering to a surface of an article. Particularly, the present invention relates to a technique for forming a cleansing/scraping media flow blasted from a nozzle toward a surface to be treated. Such cleansing/scraping media include media for a cleansing operation or a scraping operation, and media for both the cleansing operation and the scraping operation.
The present application is based on Japanese Patent Applications No. Hei. 11-74627, 11-239395 and 11-239396, which are incorporated herein by reference.
2. Description of the Related Art
As background-art cleansing methods, there are generally carried out a method of applying detergent liquid to the surface of a subject to be cleansed, rubbing the surface with a brush or the like and rinsing the surface with water, or a method of spraying high pressure water or steam onto the surface of a subject to be cleansed to thereby cleansing or scraping dirt or adhesive matter adhering to the surface. There is also known a method in which a low pressure gas flow carrying droplet-like or mist-like fluid is sprayed and then cleansing is performed by a blast flow having a high speed and a large sectional area (Japanese Patent Publication No. Hei. 5-86274). Further, there is known a method in which a soluble powder-like substance such as sodium acid carbonate or the like is added to fluid, and the pressured fluid is sprayed, so that cleansing is carried out with a physical cleansing operation based on an impact action of the soluble powder-like substance material (Japanese Patent Publication No. Hei. 8-168729). In addition, there is known a dry blast apparatus for high speed blasting of a low pressure air flow carrying a polishing/cleansing material (Japanese Patent Publication No. Hei. 1-60392).
In the background art in which a high pressure fluid or low pressure gas flow carrying droplet-like or mist-like fluid is sprayed to carry out cleansing, however, a blast flow of the high pressure fluid or the droplet-like or mist-like fluid is prevented from reaching a surface to be cleansed by a thin film layer formed on the surface to be treated, so that the cleansing operation is lowered. Moreover, in the case of using the low pressure gas flow, it is necessary, as a prerequisite, to supply a large quantity of gas. Therefore, a pressure gas generator having a low- pressure and large-quantity discharge performance such as a Roots blower or the like was used as a background-art pressure gas generator. That is, there was a problem that the degree of freedom to select the kind of the pressure gas generator was small, the size of an apparatus tended to be large, and further the diameter of a gas supply pipe from the pressure gas generator to a mixer became large.
Further, in the cleansing method where powder of sodium hydrogen carbonate or the like is added to fluid, and the fluid is sprayed for cleansing, gas is not added to the cleansing/scraping media flow aggressively. Therefore, it was difficult technologically to form a blast flow which was uniform, stable and large in its sectional area.
Still further, since the dry blast means easily damaged a surface to be treated, the dry blast means was difficult to be applied to the case where cleansing was performed merely to remove stains adhering to the surface.
The present invention has been developed in view of the foregoing background-art technological circumstances.
It is an object of the present invention to improve such a cleansing operation in the background art more greatly.
It is another object of the present invention to develop a cleansing/scraping technique effective in the operation of scraping adhesive matter adhering to a surface of a subject as well as in the operation of cleansing the surface. In that case, it is another object of the present invention to provide a mixture flow formation technique in which a more excellent mixture flow as the base of the cleansing/scraping operation is formed so that a superior cleansing/scraping operation can be ensured.
It is still another object of the present invention to provide an improved cleansing/scraping technique in which various treatment modes, for example, a mode chiefly having a cleansing operation, a mode chiefly having a scraping operation, or a mode formed of a combination of the both, can be selected in accordance with necessity.
It is still another object of the present invention to provide a technique for forming a cleansing/scraping media flow, in which a desirable kind of apparatus such as a turbo blower, or reciprocating or rotating compressor or the like other than a Roots blower can be selected as the above-mentioned pressure gas generator effectively in miniaturizing the external shape as an apparatus or a gas supply pipe reaching a mixer, and a cleansing/scraping media flow which is uniform, stable and large in its blast flow sectional area can be obtained easily.
The present invention commonly employs, as a basic configuration, such a technical means comprising the steps of: connecting a pressure fluid supply means to a mixer so as to blast fluid at a high speed in the mixer; supplying gas and powder to a flow of the fluid to thereby form a mixture flow composed of the gas, the fluid like droplets and the powder; and blasting the mixture flow from a nozzle at a high speed to thereby spray the mixture flow onto a surface to be treated, so that impact actions held by the powder and the droplet-like fluid as cleansing/scraping media are given to the surface to be treated so as to carry out a cleansing/scraping operation. As described above, the present invention has a configuration in which a pressure fluid supply means is connected to a mixer so as to blast fluid at a high speed in the mixer, and gas and powder are supplied to a flow of the fluid. Accordingly, large kinetic energy of the high speed fluid flow is used for catching the gas or powder in the fluid flow so that a superior mixture flow composed of the droplet-like fluid, powder and gas can be formed. Then, the mixture flow is blasted from a nozzle at a high speed, and the powder contained in the mixture flow breaks a thin film layer of the fluid formed on a surface to be treated, reaches the surface to be treated, and gives an impact action to the surface directly. As a result, the impact action of the powder simultaneously cooperates with the impact action of the droplet-like fluid blasted at a high speed so that the cleansing/scraping operation is improved.
The internal space of the mixer may be divided into an upstream space and a downstream space by a partition wall having a small hole, so that fluid is blasted at a high speed into the upstream space on the upstream side of the partition wall, gas is supplied to the upstream space to thereby form a droplet-like fluid flow, and powder is supplied to the downstream space on the downstream side of the partition wall to thereby form a mixture flow of the gas, the droplet-like fluid and the powder, the mixture flow being blasted at a high speed from a nozzle.
In that case, when gas is supplied to the upstream space on the upstream side of the partition wall, a large quantity of gas may be supplied through a pressure gas supply means. Likewise, when powder is supplied to the downstream space on the downstream side of the partition wall, a large quantity of gas together with the powder may be supplied through a pressure gas supply means. Then, the large quantity of gas functions as carrier gas, which is extremely effective in forming a large-diameter and high-speed blast flow when the mixture flow composed of the droplet-like fluid and the powder as cleansing/scraping media is blasted from the nozzle. Then, if the fluid and/or gas used in the present invention are heated in advance, the cleansing/scraping operation can be further accelerated. Steam may be used as the heated gas in that case.
In addition, treatment modes can be selected by adjusting the supply conditions of the pressure fluid, the gas or the powder. That is, various treatment modes from a treatment mode for a cleansing operation to a treatment mode for a scraping operation can be selected by adjusting the supply quantities in the fluid supply passage, the gas supply passage and the powder supply passage or selecting specific kinds of supplies, for example, by selecting the particle size of the powder. In this specification, xe2x80x9ccleansing/scrapingxe2x80x9d means xe2x80x9ccleansing and/or scrapingxe2x80x9d. Further, detergent and/or wax may be supplied to the mixer.
As modes for carrying out the present invention, a wide variety of treatment modes from a treatment mode used exclusively for cleansing to a treatment mode used exclusively for scraping can be selected by adjusting the supply quantities and kinds of fluid, powder and/or gas, as described above. That is, if the supply quantity of fluid or gas such as air is increased while the supply quantity of powder is decreased or if powder having a small scraping effect is adopted, the treatment mode can be set to a mode where the cleansing operation accounts for a large rate. On the contrary, if the supply quantity of fluid or gas is decreased while the supply quantity of powder is increased or if powder having a large scraping effect is adopted, the treatment mode can be set to a mode where the scraping operation accounts for a large rate.
Appropriate fluid such as water, water with an additive of surfactant, or the like, may be used as the above-mentioned fluid. Then, the size of droplets of the fluid can be selected from a fine mist-like size to a large size in accordance with the treatment mode. As the above-mentioned powder, soluble substances which are dissolved in the above-mentioned fluid after the cleansing/scraping such as sodium acid carbonate, dry ice, granular ice, salt, or the like, other than general polishing/cleansing material such as alumina, may be used so as to be dissolved in the above-mentioned fluid after the cleansing/scraping. Then, as for the form of supplying this powder to the mixer, the powder may be supplied in the form of a media stock solution composed of fluid mixed with the powder though it may be supplied directly as it is. On the other hand, as for the form of supplying the above-mentioned fluid or gas to the mixer, the fluid or the gas may be supplied at a room temperature or supplied at a moderately heated state. In that case, steam may be used as the heated gas supplied to the mixer. Then, a suitable heating source such as electrically heating means, combustion heat, steam, etc. may be used as means for heating the fluid or gas. When heated fluid or gas is used, the temperature of the fluid forming a mixture flow is increased so that the cleansing/scraping operation is accelerated. As a result, the effect of the operation is also improved on a large scale. Particularly, in the case where soluble powder is used as the aforementioned powder, the powder becomes easy to be dissolved in hot water or steam due to the temperature rising. Accordingly, by adjusting the solubility through the temperature control by heating, it is also possible to adjust the impact action of the powder. Further, when a large quantity of gas is to be supplied through a pressure gas supply means, an air blower suitable for low pressure and large quantity, such as a Roots blower, a turbo blower, or the like, may be used. Alternatively, a reciprocating or rotating compressor may be used while the pressure is reduced moderately for low pressure and large quantity.
The present invention employs such a technical means comprising the steps of: blasting at least pressure fluid and pressure gas into a mixing space in a mixer at a high speed to thereby form a high speed mixture flow of the pressure fluid and pressure gas; and sucking gas by an ejector effect based on the high speed mixture flow to thereby blast a cleansing/scraping media flow containing the fluid like droplets from a nozzle. In the present invention, carrier gas or forming and carrying a cleansing/scraping media flow includes pressure gas supplied to the mixer and gas sucked by an ejector effect based on the above-mentioned high speed mixture flow. When the pressure gas is blasted into the mixing space in the mixer, the pressure gas expands suddenly, and increases its speed while forming a mixture flow with pressure fluid supplied simultaneously, so as to form a high speed mixture flow containing the droplet-like fluid. In that case, when a small quantity of fluid is supplied to the pressure gas at a high speed, the speed of the mixture flow forming cleansing/scraping media can be prevented from lowering. In addition, another gas sucked by the ejector effect based on the high speed mixture flow is added so that the mixing of the mixture flow is accelerated. It is therefore possible to easily form a cleansing/scraping media flow which is extremely superior in the distribution of droplets. In addition, since gas is sucked by the ejector effect based on the high speed mixture flow of gas and fluid, a large quantity of gas can be sucked in comparison with the case of an ejector effect based on a high speed flow composed of only pressure gas. Thus, gas sucked by the ejector effect is added to the pressure gas as carrier gas for carrying the cleansing/scraping media. Therefore, pressure gas is not limited to background-art low pressure gas, but various modes an be carried out by adjusting the pressure or supply quantity of the pressure gas or the quantity of gas to be sucked.
Further, the mixing space in the mixer may be divided into an upstream space and a downstream space by a partition wall having an aperture portion, and at least pressure fluid and pressure gas are blasted at a high speed into the upstream space on the upstream side of the partition wall to thereby suck gas by an ejector effect based on a high speed mixture flow of the pressure fluid and pressure gas, while powder or detergent is supplied to a desirable space, that is, either one of or both of the upstream side and downstream side spaces of the above-mentioned partition to thereby form a cleansing/scraping media flow containing the gas, the droplet-like fluid and the powder. Then, if the above-mentioned pressure fluid and/or pressure gas used in the present invention are used in the state where they are heated in advance, the cleansing/scraping operation can be further accelerated. In that case, steam may be used as the pressure gas. In addition, treatment modes can be selected by changing the supply conditions of at least one of the above-mentioned fluid, gas, powder and detergent. That is, the pressure or supply quantity of the pressure fluid or the pressure gas, the quantity of gas to be sucked, and so on are adjusted through control valves or the like provided in their supply passages respectively. Alternatively, the supply quantity of the powder or detergent is adjusted, or the specific kinds of supplies, for example, the particle size of the powder, or the like, are selected. Thus, various treatment modes can be selected from a treatment mode exclusive for a cleansing operation to a treatment mode exclusive for a scraping operation.
As modes for carrying out the present invention, any form may be taken so long as at least pressure fluid and pressure gas are supplied to a mixer so as to form a high speed mixture flow. That is, a form in which pressure fluid and pressure gas are supplied to thereby form a mixture flow composed of only the fluid and gas may be adopted, or not to say, a form in which powder and so on are added to the mixture flow in accordance with necessity may be adopted as shown in the following embodiment. In addition, if the supply conditions or kinds of the above-mentioned pressure fluid, pressure gas, sucked gas, powder and/or detergent are adjusted, treatment modes can be selected in a wide range from a treatment mode exclusively used for cleansing to a treatment mode exclusively used for scraping. For example, if the supply quantity of fluid or gas such as the air is increased and the supply quantity of powder is decreased or if powder having a small scraping effect is adopted, the treatment mode can be set to a mode where the cleansing operation accounts for a large rate. On the contrary, if the supply quantity of fluid or gas is decreased while the supply quantity of powder is increased or if powder having a large scraping effect is adopted, the treatment mode can be set to a mode where the scraping operation accounts for a large rate. Then, as for the form of supplying powder to the mixer, the powder may be supplied in the form of a media stock solution composed of fluid mixed with the powder though it may be supplied directly as it is. On the other hand, when the above-mentioned pressure fluid, pressure gas, sucked gas, powder or detergent may be supplied to the mixer after they are heated in advance, a cleansing scraping operation can be improved. In that case, steam may be used as the pressure gas supplied to the mixer. Then, a suitable heating source such as electrically heating means, combustion heat, steam, etc. may be used as means for heating the fluid or gas. When heated fluid or gas is used in such a manner, the temperature of the fluid or the like forming a mixture flow is increased so that the cleansing/scraping operation is accelerated. As a result, the effect of the operation is improved on a large scale.
Features and advantages of the invention will be evident from the following detailed description of the preferred embodiments described in conjunction with the attached drawings.